Expose embedded client context from KafkaStreams threadMetadata

Details

Description

A KafkaStreams client today contains multiple embedded clients: producer, consumer and admin client. Currently these client's context like client id are not exposed via KafkaStreams. This ticket proposes to expose those context information at the per-thread basis (since each thread has its own embedded clients) via ThreadMetadata.

This also has an interplay with KIP-345: as we add group.instance.id in that KIP, this information should also be exposed as well.